Purpose
The purpose of this page will be to provide regular project briefs. These briefs will include recent progress made, conferences attended, papers submitted and presentations given, as well as downloadable resources added to the Downloadable Resources page.
If you would like to receive email updates, please inform Marcus Dersch by emailing him at mdersch2@illinois.edu with the subject of the email being “Please Add to Crosstie and Fastening System Update Distribution List”.
Briefs
17 June 2013
Field Research Video:
Video highlighting the field research efforts and how they tie into the rest of the research project.
Recent Progress:
The most exciting update pertains to the successful completion of our second field experimentation effort. Almost our entire team (15 members at different times during the week) traveled to TTC to repair previous instrumentation, install new instrumentation, and collect more data that will further our knowledge of the demands placed on the components within the crosstie and fastening system between May 16 – 24. In preparation for this field experimentation a considerable amount of laboratory work was completed to refine previous instrumentation methodologies and develop a novel method to capture the lateral load imparted into the shoulder/insulator post.
Additional laboratory experimentation has focused on studying the cracking behavior of the concrete crosstie when subjected to various known vertical and eccentric loads while also varying the support conditions. Additionally, though some minor refinement will continue throughout the project, our modeling team has completed the 3D FE multi-crosstie and sub-assembly models which will allow us to begin running parametric analyses to determine the critical parameters which affect the design of the crosstie and fastening system and further develop our simplified design tool (SLApS).
Current Focus:
Some of the items the research team at UIUC is currently working on are:
– Analysis of data from May 2013 field experimentation (estimated point of significant completion is October 2013 with additional analysis to continue into 2014)
– Execution of additional laboratory experiments to further refine the models and further our understanding of the demands placed on each component
– Completion of the design and construction of the full-scale laboratory experimental loading system (estimated completion is August 2013)
– Development of a simplified analytical design tool (SLApS) (estimated completion date is May 2014)
13 February 2013
Recent Progress:
Laboratory testing has focused on understanding the demands placed on each component within the fastening system and providing data to the FE modeling team. Multiple experiments were successfully completed in our lab that provided insight into the demands placed on the clip and insulator. Our modeling team has been able to utilize the data from these tests to improve the FE model being produced. Finally, the group has continued to process and analyze the data from the 2012 Field Instrumentation trip at TTCI. Beyond answering questions pertaining to the effect of speed, curvature, support condition, and load on the demands placed on the track, we are also utilizing this data to improve upon our instrumentation plan to allow us to capture additional data to answer questions that we currently are unable to answer.
A subset of the research team attended the IHHA conference in New Delhi, India and gave presentations on the FE model, findings from the 2012 field experimentation, rail seat pressure distribution, mechanistic design of the crosstie and fastening system, and an investigation of the mechanics of RSD and methods to improve the abrasion resistance of concrete rail seats. These and other presentations can be found and downloaded from the Downloadable Resources page.
Current Focus:
Some of the items the research team at UIUC is currently working on are:
- Developing new methods to the lateral load placed on the clip, insulator, and shoulder, as well as the displacements of the crosstie and pad assembly
- Improving upon current methods to quantify rail displacement and rotation
- Completing the design and beginning the construction of the full-scale laboratory experimental loading frame
- Continuing to validate the single and multi-crosstie FE models
- Developing a simpliefied analytical design tool
- Improving upon the experimental run matrix
8 November 2012
The concrete crosstie and fastening system research team was in Tampa, FL for a project update meeting with the FRA, a meeting with their Industry Partners, as well as attending and participating in the AREMA Committee 30 and Subcommittee 4 meetings. The group received very quality feedback and critical comments.
All presentations can now be found on the Downloadable Resources page.
If you would like to be added to the email list to receive notices regarding project updates, please inform Marcus Dersch by emailing him at mdersch2@illinois.edu with the subject of the email being “Please Add to Crosstie and Fastening System Update Distribution List”.
31 August 2012
The concrete crosstie and fastening system research team at the UIUC is excited to provide an update regarding the work that has been underway this summer. Progress has been made in both our laboratory and field experimentation programs as well as our Finite Element Modeling (FEM) capabilities.
Laboratory testing has primarily been focused on improving our field instrumentation strategy. Multiple tests were successfully completed in our lab that provided much needed insight into the intricacies of our instrumentation and data acquisition strategy. Furthermore, our modeling team has been able to utilize the data from these tests to increase our confidence in our FE models. Therefore, the results from these tests, once plugged into our models, have provided additional details into the behavior of many of the components within the tie and fastening system.
One major accomplishment this summer was the successful completion of our first major field test at TTCI. To prepare for this field testing, our group has been holding weekly meetings since November of 2011. Further preparation consisted of casting instrumented ties to provide a means to measure the loads transferred into the rail seat and further understanding the bending of each tie under load. This was only accomplished with the tremendous support of CXT Concrete Ties. A sub-set of our group traveled to CXT in Tucson, AZ in late May and internally instrumented the ties via installing embedment strain gauges on the prestress wire in the rail seats of selected crossties. These ties were also externally instrumented with concrete surface strain gauges. We are also very grateful to Amsted RPS for providing the fastening systems for our test sections.
The ties were then shipped to TTCI and installed in mid-July. Once our ties were installed, TTCI installed strain gauges and global displacement ground rods per the UIUC instrumentation plan. Our entire group then arrived and completed the instrumentation installation which included additional strain gauges on the clips and insulators, pressure sensors on select rail seats, displacement transducers on the rails and ties, and temperature transducers on select pads. Testing was completed in a curve on the HTL and on tangent track on the RTT. We tested at both sites with TTCI’s TLV, a 9-car passenger consist, and a 9-car freight consist. We tested at speeds ranging from
2 -102 mph on the RTT and 2 – 45mph on the HTL. In total, we have estimated that in the 261 individual tests completed, we acquired over 1 billion data points. Therefore, we are currently analyzing this data and will be able to produce some meaningful graphs in the near future.